We'll know after November how well he came across to blacks.
But Trump often uses hyperbole to make his points: his point is that the black community has suffered under Obama---even Farrakhan makes the same claim. The ever...ever bit is hyperbole. Obviously, Trump doesn't think the black community was better off before the Civil War and I think most people, including black people get that.
Hyperbole is a legitimate rhetorical device.
Democrats know they're vulnerable with the black vote so they will demonize Trump's outreach every chance they get.